Common widely used vaccines are made from pathogens (e.g., microorganisms, viruses) or such pathogens whose toxicity is partially weakened or eliminated. The vaccines are administered to living bodies to induce immunity to prevent infectious diseases. Most of the vaccine formulations commercialized at present are injection products.
Injections, such as subcutaneous injection, intradermal injection, and intramuscular injection, are commonly used in administration of a vaccine for induction of immunity. In particular, since microorganisms or viruses cannot enter the body through the skin due to their sizes, invasive administration of a vaccine into the body is needed.
Injections, however, have problems of psychological burdens on patients, such as pain, fear, needle marks and scarring thereof, and the burden of visiting the hospital in their daily lives in a case where repeated administration is required. Additionally, injections further have problems that only medical practitioners can give them, that the intradermal injection which gives a high immune effect requires a proficient skill to give, that medical professionals are exposed to a risk of infection due to needle pricking, and that medical waste which necessitates special disposition, such as injection needles, is generated. Injection is therefore not necessarily the best administration route.
To overcome the situation, vaccination through the mucosa has attracted attention and mucosal administration (transnasal administration and oral administration)-type vaccines containing influenza virus as an antigen have been developed. For example, Patent Literature 1 discloses a case where immunity can be induced by transnasaly administering a Pantoea bacterium-derived lipopolysaccharide as an immunostimulant together with an antigen. According to Patent Literature 2, oral administration of a vaccine containing a Pantoea bacterium-derived lipopolysaccharide sufficiently induces an immune response.
However, it is highly possible that administration of an antigen through nasal mucosa gives severe side effects such as acute encephalopathy, though it gives a high effect. In addition, transnasal administration itself is complicated and difficult in the case where the administration subject is an elderly person or a baby. Moreover, physical factors such as snivel may inhibit stable exertion of the effect.
Whether or not immunity can be induced by transdermal administration of a vaccine containing a Pantoea bacterium-derived lipopolysaccharide has not been disclosed, and the dosage form appropriate for transdermal immunization has not been disclosed.